1. Field of the Invention
The present invention is directed to a process and apparatus for automated vehicle-autonomous detection and identification of a traffic condition or situation, and in particular to the automated detection and identification of backed-up traffic or traffic jams. In addition, the invention defines a set of criteria or rules for automatically determining the navigability of streets based on the determined traffic flow.
2. Description of the Related Art
An essential task in the field of transport telematics is to determine and describe the traffic situation with the aim of correcting and preventing traffic backup situations as far as possible by foresighted diversion of road users to less crowded routes. To accomplish this purpose it is known to use detection devices, as for example beacons, induction loops or the like, that are installed in a stationary manner with respect to the road. These stationary detection devices not only incur very high costs in order to provide and maintain the necessary infrastructure, but also are disadvantageous in that they have an extremely narrowly defined useful local range for reasons inherent in the system. Therefore, it is necessary to install a multitude of such detection devices in order to determine the traffic situation over a wide area of interest.
Recently, devices have been developed that detect traffic situations without the use of stationary devices by transmitting appropriate information from vehicles, otherwise known as "floating probes", to suitable data collecting stations such as central traffic control offices. In particular, these non-stationary devices include measurement stations floating or traveling along with the traffic i.e. "floating probes" which transmit relevant data, notably vehicle speed, using a mobile wireless communications device such as a radio telephone to respective data collection points or stations for further processing and evaluation. The information is evaluated at the collecting station and the results may be transmitted to a large number of road travellers as traffic guidance and recommended detours so that the traveller may select the best possible route based on the traffic situation. The results may also serve as input for automatic route guidance and navigation systems.
A problem with such "floating probes" is that the continuous transmission of the current speed of a plurality of vehicles often times imposes an extraordinarily heavy burden on the transmission channels of the communications device in addition to a significant expense when using a toll communications system. These problems must be considered in light of the fact that a substantial amount of the transmitted information does not actually provide different or changing information. Therefore, it would be advantageous to limit the transmission of information, at least for the most part, to instances in which critical traffic situations occur, have already occurred or recur. To limit the information transmitted in such manner would require a determination of the time periods during which significant changes in road traffic in terms of traffic management occur. Using conventional floating probes, the information may be transmitted under the control of individuals in or among the floating probes, so-called "traffic jam reporters", as needed depending on the relevant traffic situation. However, this is disadvantageous in that it not only requires a corresponding willingness on the part of the reporters, but is also subject to deliberate or unwitting transmission of incorrectly appraised traffic situation data.
Therefore, it is the object of the present invention to provide a process and device for automated detection of a traffic situation, and in particular of traffic congestion and jams, onboard a vehicle which is independent of reporters or manual interaction.